Automatic regulating device for heating systems



Feb; 9 1926.

H. SCHMELZ AUTOMATIC REGULATING DEVICE FOR HEATING SYSTEMS Filed Sept. 5, 1922 2 Sheets-Sheet 1 Feb. 9 1926.

H. SCHMELZ AUTOMATIC REGULATING DEVICE FOR HEATING SYSTEMS Filed Sept. 5. 1922 2 Sheets-Sheet 2 m m ,L 1/

Patented Feb. 9, 1926.

' UNITED STATES CHENEY SCHMELZ, 0F WILLARD, NEW YORK.

'AUTOMATIG REGULATING DEVICE FOB HEATING SYSTEMS.

Application filed September 5, 1922. Serial No. 588,245.

To all whom it may concern:

Be it known that I, HENRY ScHMELz, a citizen of the United States, and a resident of the city of Willard, county of Seneca, State of New York, have invented an Improvement in Automatic Regulating Devices for Heating Systems, of which the following is a specification.

This invention relates to the automatic regulation of temperature in heating systems or the like.

Among other objects, the invention is intended to provide an improved and reliable device for controlling the fire in a heating system and minimizing waste of fuel.

The invention consists in the novel constructions, combinations and arrangements, hereinafter described or claimed, for carrying out the above stated objects and such other objects as may appear from the following specification.

The nature of the invention may be best understood by reference to one illustrative construction embodying the invention and illustrated in the accompanying drawings.

In said drawings:

Fig. 1 is a diagrammatic view illustrating a heating system and devices for regulating the same.

Fig. 2 is a plan view, partially in section, of an automatic damper.

Fig. 3 is a vertical section taken along the line 3-3 of Fig. 2.

Fig. 4. is a vertical cross-section taken along the line 4-4 of Fig. 3.

The automatic damper illustrated in the drawings is intended to be placed in the flue pipe of the ordinary heating system. It is particularly adapted for heating systems for residences or the like, which do not have an attendant constantly present,-

and to operate and re late which expensive automatic control mec anisms would be prohibitive.

This automatic damper comprises a casing or housing 10 which may be of any suitable cross-section, having ends 11 to which flue pipes may be fitted. As illustrated, these ends 11 are circular collars and the casing 10 is of rectanguler section. One side of the casing is preferably provided with a hinged door 12 for gaining access to the interior for purposes of adjustment andcleaning.

Secured to the upper side of the casing 10 is a bracket 13 having angular ends between which a wire 14, such as a piano wire of sufficient strength, is stretched. One end of the wire is secured to one angular end of the bracket and the other to a threaded bolt 15 having a nut 16 by means of which the tension in the wire 14 may be regulated. Hinged to the wire, by means of hinge members 17, is a damper plate 18 of rectangular shape. The hinge members 17 are riveted or otherwise secured to the plate and provided with holes near the ends through which the wire 14 passes. The damper plate is smaller in size than the cross-sectional area of the casing 10 to provide a space 19 to permit a certain amount of leakage of flue gases even when the damper plate is entirely closed. The lower end of the plate is cut away at 20 to rovide additional s ace and the sides t ereof provided wit flan ed extensions 21 for engagement with t e ends 22 of the housing to permit additional space 23 for leakage so that the damper plate can not completely close the passage through the casing. The amount of leakage intended to be permitted is that which is little more than sufiicient to prevent extinguishment of the fire and the improper escape of products of combustion into the surrounding atmosphere. I

Secured to the plate is an arm 24 which passes through the casing to the exterior in line with the axis of the hings of the plate. For this purpose the extremit 25 of the arm is offset, providing an intermediate angular portion 26 which, when the plate swings a out its hinge, always rotates on the axis of the hin e. The portion 25 of .the arm is threaded and provided with a counter weight 27 which may be adjusted to balance or overbalance, 'asdesired, the damper plate in any position.

The damper plate is also provided with a counter pressure poise 28 carried on an arm 29 mounted on the damper plate. The arm 29 is threaded to permit adjustment of the counter pressure poise.

In the construction illustrated the automatic damper is arranged to be mounted in a horizontal flue pipe. The flue gases travel from left to right (Fig. 3) in the direction of the arrow. Normally the damper plate assumes the position indicated in dotted lines in Fig. 3. The pressure of flue gases tends to swing the damper plate about its hinge to close the same and restrict the passage through the casing. When the counter pressure poise asses beyond the vertical plane through t 1e hinge, it increasingly resists the further closing of the damper by the pressure of the flue gases. The farther this counter pressure poise extends beyond the imaginary vertical plane referred to, as indicated in full lines in Fig. 3, the greater its turning moment (about the hinge in a clockwise direction) tending to open the damper plate against the pressure of the flue gases. Thus a balance is effected between the pressure of the flue gases and the counter turning moment ofthe counter pres sure poise 28, and the damper plate assumes a position depending directly upon the pressure of the flue gases. By means of adjusting the weights 27 and 28 on their respective arms the relation between the position of the damper plate and the cor-responding pressure of flue gases may be varied.

Obviously, by roper selection and adjustment of weig ts, this damper may be employed in a vertical flue pipe.

Dirt will not collect in the damper casing when the same is in vertical position. When in horizontal position, the velocity of gases is greatest along the bottom through the restricted space 23; thus the flue gases will carry along with them any dust or dirt which collects upon the bottom of the easing. There is substantially no friction in the hinge because the wire acts somewhat as a knife edge. No dirt can collect to interfere with the freedom of movement of the plate on its hinge.

The device may be adjusted to maintain the fire in any desired condition. iAny variation in the intensity of the draft, due to change of tem erature, air conditions or otherwise, is chec ed by the change in position of the plate in response to the variation in pressure of the flue gases. In other words, the automatic damper tends to maintain the desired condition of the fire. A falling off in the draft permits the plate to open, and thus automatically decreases the resistance to the flow of flue gases. This tends to increase the volume of the draft and when it again attains the desired amount the damper acts as a check to its continued increase and vice versa.

The device herein illustrated is particularly useful in combination with the ordinary thermostatically controlled heating systems for dwellings and the like. Such a system is illustrated diagrammatically in Fig. 1, in which the furnace 30 is provided with means 31 for regulating the draft through the ash door 32 or equivalent draft inlet. The means 31 is controlled by thermostat 33 located at some suitable place or room in the dwelling which it is desired to maintain at the desired temperature. I have illustrated a thermostat which controls the means 31 through an electrical circuit 34. This is merely by way of illustration. Any other type of thermostat and controlling mechanism may be employed. The automatic damper is placed in a suitable position in the flue pipe 35, as illustrated.

In such a system there is a characteristic lag in the response of the fire to the control of the thermostat, which in such systems is usually located in one of the rooms heated and regulates the fire by the adjustment of the draft. When the temperature of the room falls below the desired degree, the thermostat acts to open the draft, but since the increased temperature of the fire cannot immediately return the temperature of the room to the desired degree, the fire becomes, under the increased draft, much more intense than necessary. Its intensity increases for a considerable time after the thermostat has reduced the draft and of course the temperature of the room rises considerably above the desired degree be- 1flore the reduced draft sufliciently cools the This surging of the fire is characteristic of this type of thermostatic control. It is impossible to effect a stable balance between room temperature and the drafts, and accordingly temperature regulation is effected by alternately increasing and decreasing the draft begond the theoretically correct amount, t e fire and the resulting temperature surging above and below the desired.

By employing the automatic damper, above described, in the flue of such a thermostatically controlled heating system, the extreme surging of the fire is prevented. As soon as the velocity of the flue gases increases substantially beyond the proper amount, the increased pressure on the damper causes it to close further and reduces the effective cross section of the flue. This automatically reduces the intensity of the fire. Since, as above explained, the intensity of the fire in such thermostatically controlled systems always exceeds that necessary to restore the proper temperature conditions before the thermostat itself acts, the more prompt action of the damper prevents the excessive intensity of the fire and reduces the amount of surging in both the fire and the resultant temperature. The adjustment of the damper to effect this result is such that it merely causes the damper further to restrict the flue passage, but not to close fully, upon the usual increase in flue gas velocity.

To accomplish this cooperation between thermostat and damper, the weights on the conditions damper are adjusted to maintain, as far as.

possible, the fire in the condition, which, under ordinary circumstances, will produce the proper room temperature. With this adjustment, the damper will resist-substantial variations in flue gas velocity. This does not mean that it will absolutely prevent changes in velocity, under certain conditions, but it will resist such changes and tend to restore and maintain the desired flue gas velocity. It merely opfposes and prevents the wide variation in ue gas velocity which would result from the unhampered operation of the thermostat. This resistance to change prevents the surging in the fire which would ordinarily result from the opening and closing of draft responsive to the thermostat.

Although the damper serves to prevent excessive surging of the fire, even when not used in combination with a thermostatically controlled system, it does not effect of the wind, condition of the air, ventilation,

leakage, etc., the damper alone does not always reliably regulate' the room temperature. "lVhen used in combination with a thermostatically controlled system, the automatic damper does not'control the fire so much as it improves the temperature regulation of the thermostat by preventing surging of the fire.

Obviously, the invention is not limited to any specific form of construction and the details of the illustrative device may be variously modified. Moreover, it is not indispensable that all features of the invention be used conjointly; they may be employed advantageously in various different combinations and sub-combinations.

I claim- J 1. An automatic damper comprising in combination a housing having a hinged damper valve therein, means for balancing said valve about its axis, said damper valve being arranged to close when moved in the direction of travel of the flue gases, and a counter pressure means for balancing the damper valve responsively to the pressure of the flue gases thereon.

2. An automatic damper comprising in combination a housing having a hinged damper valve therein, means for balancing damper valve and holding said damper in a predetermined position depending upon the velocity of the flue gases.

3. An automatic damper comprising in combination a housing, a hinge wire stretched across said housing, a damper plate hinged along one edge to said wire, means for balancing said plate about said wire and a counter pressure poise connected with said plate to resist the closing of said damper plate by the pressure of the flue gases.

4. An automatic damper comprising in combination a housing having a hinged damper plate therein, an adjustable counter balance on the exterior of said housing and connected with said plate, and a counter pressure poise connected with said plate and having a turning moment about the hinge of said plate opposed to that of the pressure of the flue gases.

5. An automatic damper comprising in combination a housing, having means for connecting the same to a flue pipe or the like, a damper plate hinged within said housing to vary the effective passage through said housing, and means for operatively balancing said damper plate in said housing independently of the position of said housing, said means consisting of a counter balance weight for balancing said plate about its hinge and a counter pressure poise connected with said plate for balancing said plate against the pressure of flue gases thereon.

6. The method of improving the temperature regulation of a thermostatically controlled heating system of the type described, which consists in resisting substantial variations in flue gas velocity responsive to the operation of the thermostat.

7 The method of improving the temperature regulation of a thermostatically controlled heating system of the type described, which consists in resisting substantial variations in flue gas pressure in proportion to the intensity of such pressure.

In testimony whereof, I have signed my name to this specification.

HENRY SCHMELZ. 

